After being sworn in, Greenspan admitted there were "an awful lot of mistakes" in his 21 years in office, but that he was right 70 percent of the time. He acknowledged some actions taken in the build-up to the crisis could be included in the 30 percent of times that he was wrong. But Greenspan also argued that regulators could not be expected to fully predict or prevent crises. "The recent crisis reinforces some important messages about what supervision and examination can and cannot do," he told the panel.

Greenspan also said the development of some complex mortgage instruments was not improper, but boosted "the national policy of making homeownership more broadly available."

What rationale can you use to argue that Credit Default Swaps helped people get homes? I guess you could say that masking extremely risky mortgages by chopping them up and rating them as AAA allowed banks to offer loans to people who couldn't afford them. Not sure I would use that as an argument to defend myself though.